Solution consisting of a polymeric n-vinyl pyrrole compound and chloroform



Patented Nov. 2, 1948 mm-:3"?

UNITED, STATES" "PATENT. 'o r rs cn s.

2,453,097 I fl SOLUTION oonsis'lu wej CHLOROEOBM y Michael T. Orinik, BinghamtOnQNS-XL; assignor l i toGeneral Aniline & Film CorporatiomqNew Yorlg N. Y., a corporation Delaware l Serial No. 627, 4 Claims. (CL; h

This invention relates to the manufacture of ripp ng aids. This added step in theiicasting sheets, film, or foils composed of polymeric N- process is not satisfaotorybeoause"ldliinr a-'convinyl compounds. More particularly, the inventiriuousi cas'tingprocess,:the surfacemust be thortion relates to a method of facilitating the reoughly'dried for subsequent-casting of solutions moval ofsuch sheets, films and foils from the fit-L of the said polymers; and .(b) an .added foil drysurface upon which they are cast. I ing procedure" is rnecessaryiafter. stripping. I i Polymeric N-vinyl pyrroles of a molecular An object of the present invention-istot-avoid weight sufficient to produce self-sustaining films the above-mentioned,=diificulties and to provide a and foils, such as polyvinylcarbazole, polyvinylmeans whereb suchfilms, sheets, 01' foils may be isopropylcarbazole, polyvinyltetrahydrocarbazole,old strippedfroim attesting surfacewith ease. and polyvinylindole, p01yvinylpropylcarbazole, poly- Witliout impairment o their qu l y. vinylnaphthocarbazole, and the like are described An t e Object is to provideariimproved meth in United States Patent 2,072,465. In the manud of -stripping-- polymeric N-vinyliipyrrol'e com facture from suchpolymers of sheets, foils and poundsfrom-a-castin 1films-ranging from 0,001 to. 0.05 inch in thick- 1: -:--Theserand.further objects will become apparent mess, and of any suitable width, the polymeric i t e, o lowingdescription.

N-vinlypyrrole compound is dissolved in a suit- 1 1 have-,discoveredthatl arnenabled tolachieve able solvent and a plasticizer added to make the theobjectsioftthe present invention by selecting composition which in the parlance of the trade is aisolvent w qh lnotonly acts-as a plasticizenIQ called a dope. This dope is cast on the surface-= t fi m p lym ri ,Nmin l nyrrole of a slowly rotating wheel or drum having a compo ds, a d i a ts the a r s d ysical smooth nickel or chrome plated surface, or on the .loharacteristics-thereto, but-also aids in the stripsurface of an endless metallic band, and the sol- -pine ofthe cast filmeor foilafterrdryingoi-mutin vents removed from the deposited material by 'l is solventlconsistsof chloroform. Halogenated means of heated air. Finally, the dried or cured hydrocarbons :iin ggenera ha sheen r q ently material is stripped from the casting surface in suggested for use as solvents or plasticizers for the form of a continuous sheet which is wound "various resins and polymeric materials, Rather upon a shaft for storage or. further use, such as surprisingly, however, chl orofdriiralorie of such insulating foil, protective sheeting, and. for ooatsolvrits"is"capable"of imparting-plasticityftothe ing;with emulsions to form photographic film. 50mm N vinyl "pyrrol'e"'foils"'and threatens Notwithstanding that the bulk of the solvent-has "theihterfacialadhesidfi"of'su'ch'foilsto the cast- .been removed from the filmwhen it reaches the *iiilg 'surface,so'thatthe.foils'may"be easilystripped point where it is stripped from the casting sur- T'f-r'om any one "of th'e known'casting"surfacesj ,in before recommended such as, for example, hen- Zene', toluene, Xylene, dioxane, ethylene dichlofilm or foils adheresso tightly to all known surfacessuch as, stainless steel, Monel metaLchrome l plate, copper, tin, silver, glass, resin surfaces, and

"'sed as a "single solvent; is preu's'e'd "as such ,'*itl has" the combined face, difiiculty is experienced in the removal of v chlor form the material from the casting surface. retreat "When Regardless of'the solvent employed and hereride, and the like, or mixtures thereof, the cast I my the like, that it requires considerable force to repounds leads to a lifghly flifiieri't ahd continuous move it. This causes the film to stripolf in an method for casting sheets, films, and foils which unsteady manner with considerable jerking. Viis impossible when using other solvents or solvent brations are .thus set up as theresult of which combinations. the surface of the film or foil develops cross-wise The polymeric N-vinyl pyrrole compounds used ma n s, which distinctly impairs the q y herein are, as stated, capable of producing selfof the resulting product. The adhesion is fresustaining foils and films when castifrom a soluquently so great as to cause small portions of the tion of the polymer. Generally, said polymers film to be torn away from the main body of the have a K value ranging from 130 to about 170. material and left upon thecasting surface. In practicing the present invention, any un- In order to obviate the above difiiculties, it has plasticized polymeric N-vinyl pyrrole compound of been ested that the casting su e be Wetted the type aforesaid may be employed, such as those Wlthwater or other wetting solutions, such as obtained by the procedure describedin the above then filtered by any of the conventional filtration methods to give a clear solution, free of any foreign or undissolved particles. Air, which may be present in the solution, may be removed by vacuum or by heating the solution at 50 C.60 C.

for one hour.

The clear solution of the polymeric N-vinyl pyrrole compound is then fed onto a smooth sur faced drum or endless band by means of a hopper,

which is fitted with a micrometer adjustment for foil thickness control.

Drying or curing is accomplished by passing low velocity air at 30 C.-60 C., over the cast solution in a direction counter to that of the moving wheel or band.

For a fuller understanding of the nature and objects of the invention, reference is made to the following examples which are given merely to further illustrate the invention, and they should be re garded as exemplary and not as limitative. All the parts by weight.

Example I A solution or dope is made up as follows: 7

, Parts Polyvinyl carb-azol-e (K=average of about 170) 4 chloroform 1 143 This solution was cast upon the polished periphery of a drum to form a layer which upon drying would produce a film of about 0.008 of an inch in thickness. The partially dried film was removed with ease when taken up by the guide roll leading to the drying chamber.

The advantages of the invention are brought home by contrasting the above procedure with the following, illustrating the eifect of adding a cosolvent to a chloroform solution of la polyvinyl carbazole dope from which a film is cast.

Parts Polyvinyl carbazole (K==average about 1'70) 4 chloroform 52 Toluene 91 This solution was cast in the manner described above. The partially dried film was removed with difiiculty and its surface, which was face to face with the casting surface, showed crosswise markings causing impairment of the film.

The procedure of the above example was repeated with the exception that chloroform was substituted by the same amount of ethylene dichloride. The partially dried foil in this case adhered tenaci-ously to the casting surface and could not be stripped so as to be placed on the guide roll leading to the drying chamber.

Example II Parts Polyvinyl isopropylcarbazole I '(K=average of about 130) A 8 Chloroform 138 Emample I I I Parts Polyvinyl tetrahydrocarbazole (K=average of about 130) a- 7.5 'Chlor-oform 144 The solutions of Examples II and III when cast resulted in very satisfactory films, which were readily removed from the casting surfaces and possessed the same satisfactory properties as the film of Example I.

It is evident that the solutions or dopes prepared in accordance with this invention are not limited for casting on a peripheral surface, but are also capable of being cast on endless metallic belts to give films, foils, or sheets which are cleanly stripped from the casting surface.

While the present invention has been described in considerable detail with reference to preferred procedures and materials, it is to be understood that the invention is not limited thereto and that numerous variations may be made in the procedures herein described. All such modifications and variations are within the scope of the invention as defined by the appended claims.

I-claim:

1. A solution, which upon being cast, yields foils and films of polymeric N-vinyl pyrrole compounds of improved stripping properties consisting of 3 to 8 parts by weight of a polymeric N-vinyl pyrrole compound in :to parts by weight of chloroform.

2. A solution, which upon being cast, yields foils and films of poly N-vinylcarbazole of improved stripping properties consisting of 4 parts by weight of said polymer dissolved in 143 parts by weight of chloroform.

3. A solution, which upon being ast, yields foils and films of poly N-vinylisopropylcarbazole of improved stripping properties consisting of 8 parts parts by weight of said polymer dissolved in 144 parts by weight of chloroform.

MICHAEL T. ORINIK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1 2,072,465 Reppe et a1 Mar. 2, 1937 

